Insulation of conductors used in electrical apparatus



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5 Sheets-Sheet 1 daal l l 4.1 r r C. A. PARSONS ET' AL Filed March 19, 1925 INSULATION OF CONDUCTORS USED IN ELECTRICAL APPARATUS IIIIIII r a Sept. 25, 1928.

Sept. 25, 1928.

C. A. PARSONS El' AL INSULATION OF CONDUCTORS USED IN ELECTRICAL APPARATUS .5 Smets-Sheet 2 Filed March 19, 1925 Sept'. 25, 1928.

c. A. PARSONS ET AL.

INSULATION OF CONDUCTORS USED IN ELECTRICAL APPARATUS 5 Sheets-Sheet, 3

Filed March 19, 1925 Sept. 25, 1928. 1,685,722

c. A. PARSONS ET AL INSULATION OF CONDUCTORS USED IN ELECTRICAL APPARATUS Filed March 19, 1925 lll 40 59 58 57 56 55 54 55 52 5| 50 2952827 26 24 25 Sept. 25, 1928.

c. A, PARsoNs ET A1.

INSULATION OF CONDUCTORS USED IN ELECTRICAL APPARATUS llQMrGh 19. 1925 5 sheets-sheet 5 NN MN Saw PARSONS blik jmp.

fasti# Jesse! mmm# .Patented Sept. 25, 1928i.y

UNITED STATE-s PATENT" OFFICE.

ciARnEsLGERNon Piflnsons un or NEwCsTLEiONuY'N, LAND; SAID Rosan' AssmNon'To' sAn PARSONS;

nv'sulia'rron` o'F' ooNDUc'roRs Usnnrn ELECTRICAL' APPARATUS.

Application led March`19, 1925,` Serial vNo 416.835, and in Great BrtainMay 1, 1924.

The 'present invention relates to windings used in electrical.apparatus and particularly to those carrying high voltages. f,

In such apparatus, itis necessaryto provide b sufficient insulation around the `conductors in.l

thepoi'tion's of the windings subjected: to high voltages to withstand the highest potentia'lsfgenerated in or supplied to them. In windings used in dynauio-electrie machines, l for example, whichare subjected to very hi gh potentials. the'insul'ation becomes excessively heavy andtlierefore the space available for with the' invention will be described as applied to al d ynamo-electric` machine.

25, lReferring to the accompanyingI drawings, whichrepresent diagrammatica'lly by way of example an embodimentof'the'invention Figure' 1 shows the winding in crosssection; y v y 3 Figure Q showsthe winding in cross section with'one annularl sheath ;v l

. Figure 3 shows the winding'in cross sec- 'tion' withtwo 'annular she'aths; i v` Figure 4f showsthe windingin cross seo- 3 tion with three annular she`aths;`

Figure 5 is a modification showing annular y sheaths aroundea'ch il'idividu'al conducting eleme'nt'o'f the winding; f

Figure 6 isa modification of Figure 5.

showing al sheath between the two individual conducting elements;

Figure 7 is au enlarged view of a section ot.' kthe conducting eleme'n'tin Figures 11 to 145;*y Figure 8 isL an enlarged view of a'sectionfof" the' conducting element/'in Figures 1l to 14 having one sheath; f

, Figure 9 is an enlarged view of a section of the chnductin'g element` inFigures 11 to 14e yhaving two sheaths,`and' f having threesheaths. y l A ,v f

Figures l1 to 14 show the application of the f ducting` elements.

.be formedf any conducting material,

J pltatelyi to surround the conductive?T l! ioure 10' is an enlarged view of a section 1 Y N b. 4 of the conducting element 1n Figures 11 to 14" invention to a three-phase dynaino-elec-tric machine; the four views when placed together two metallic elements, a, o, forming separate.

conducting eleniients having a cross section of :the shape of a cou'ipressed D placed back to back. insulating material, c, being arranged between the two conducting elements andalso completely enclosing'them. findings of any other suitable shape may be employed and each may contain Vone or more metallic con- Around the insulation ot these conducting elementsfa, Z), one or more annular or .con-

centric conducting sheaths, d', e, f, as shown lnFigures 2, 8 and 4, are provided, yalternat-` ing with interleaving layers of insulation., o,

`preteraloly of uniform thickness, the outer sheath', d. Abeing surroi'inded finally by an eX- ternal layer of. insulation, c. Y

Alternatively the conducting elements,a,

), mayeach be surrounded with one or more separate sheaths. y

An example is illustrated in AFigure 6 in which only one sheath, g, 7L, is shown around each conducting element, a, Z). In this case an earthing plate, lc, may be provided be` tween adjacent elements, a. b, as shown'in Figure 6, this being equivalentl to af sheath at earth potential. Or again, thewindingy may contain one con ducting element as shown in Figures '7 to l0, ind may. be provided; with f one, two, or three conducting sheaths as f shown.

The conducting sheaths are Jreferabl sl f y made of thinsheet metalin the form of thin ribbon, fine wireor sprayed on `metal, suchv l' as lead tubeor the like but instead ,of being n composed of' a metallic substance they may such, for instance, as graphitic paint. e f f The annular sheaths may be made comg elements,

or they maybe split or cut into spirals to reduce eddy losses and need not be circular in form.

An en'ibodiment of the invention, as applied to a 30.000 volt generator. is illustrated d iagra-mm atically by wayof example in Figures l1 to 14 which, when lplaced with their Q40 slots having one conductor per slot cony taining one conducting element; the windings of each phase will be distributed between SO slots, one conducting element in each slot,

which conducting elements ttor convenience will be designated by consecutive numbers. The ends ot the main winding are shown at T1 and T2 in the figures. The winding is providedwith sheaths around the conducting element in the manner shown in Figures 7 to l0, both the conducting elementI and sheaths being in inductive relation to the electromagnetic field, but no connections are made between the sheaths and the main windings andthe sheaths themselves are connected together in series so as to 'torni separate complete auxiliary windings.

Slots numbered l to -l() contain the oddnumbered conducting elements. while slots numbered 121 to 160 contain the even-numbered conducting elements. Odd-niunberedconducting elements l to and even-number-ed conducting elements Q to Q-l have no sheaths around them as shown in Figure T.

Odd-numbered conducting elements 25 to -l-.i and even-nun'ibered conducting elements Q6 to ll-it are provided with one sheath, c?, shown in Figure S. Odd-numbered conducting elements 4.o to (53 and even-numhered conducting elements 46 to 6i are provided with two sheaths, (Z and e, as shown in Figure 9, while odd-numbered conducting eleinents 65 to T9 and even-numbered conductin g elements G6 to S0 are provided with three sheaths, (Z, c, as shown in Figure l0.

rl`he innermost sheaths, around conducting elements numbered G to SO inclusive are connected in series by the connections. 7"; the inner sheaths, e, around conducting elements numbered i5 to G-l inclusive are connected in series by the connections, c, and the sheaths. (Z, around toe conducting elements numbered to -l-l inclusive are connected in series by the connections, d. These three groups are connected in series to torni a complete auxiliary winding. F, S, shown in Figures 1l to 14.

rllhe middle sheaths, c, around conductingelements numbered to SO inclusive are connected in series by the connections. e the outer sheaths. (Z, around conducting elements numbered 45 to Gel inclusive are connected in series by the connections, d. and these two groups are connected in seiies to torni a second complete and separate auxiliary winding, F2. S2. shown in Figures ll to rllhe outer sheaths, (l, around conducting elements numbered G5 to 80 inclusive are connected in series Vby the connections, d', to

torni a third complete and separate auxiliary winding. F3, S3, shown in Figures il to li.

Since each auxiliary winding is a series winding the voltage increases uniformly 'tor each turn, the increase being the same as in the main windingl since the voltages in both are induced by the same means, namely, the electro-magnetic tield. 'lhe auxiliary windings are arr ngei'l as shown in the Figures ll to lil so that the voltage induced in the innermost sheaths is lower than that in the conducting),i element but higher than 'that in the middle sheaths and the voltage in the middle shcaths is higher than that in the outer sheaths where three sheaths are employed. Similarly where two sheaths are employed the voltage in the inner sheaths is higher than the voltage in the outer sheaths but lower than the voltage in the conducting element.

The induced voltages in the sheaths are in this manner stepped down trom within outwards, thus ivvoidingl eirceiisive ditlerences ot' potential across the insulation and giving a. substantially uni'torm distribution or drop ot potential.

Or alternatively all the outer sheaths or some et them are connected in series to orm a group, and similarly with the inner and innermost sheaths, such groups or some ot them being' themselves connected in series it desi red.

ln such cases the voltages induced in said sheaths are stepped down Vtrom within outwards and the potential gradients across the insulation between the various sheaths themselves and between the sheaths and the conducting elements are uniform. i

The auxiliary winding can be employed it desired tor generatine` power at lower voltages and the power so obtained used tor auriliary or local supplies, thus avoiding the use ot step-down transformers tor this purpose.

rllhe slots in which the windings are plat-ed may be semi-open,completelyopen and ot auf,Y desired shape. ln some cases tae conducting elements themselves may be varied in area to deal with capacity currents.

Although the windii ejs have been described in the two examples gir ,n as having one and two conducting elements respectively, any number or shape oif conductin elements may be employed.

rl`he present that the electrical stress material are Ireatlv reduced and c* i he evenly distributed over the cross seeion ot the insulation and the dilliculties encountered in invention has the advantage in the insulating this connection with very high potentials are li u liu?

llll

having an electro-magnetic field, ka main Winding consisting of a conducting element and auxiliary windings composed of sheaths surrounding said conducting element and varying in number lengthwise thereof, said conducting element and sheaths being in inductive relation to said field as set forth.

2. A winding for electrical apparatus having an electro-magnetic field comprising in combination a'inain conducting element, insulation surrounding said conducting element, a plurality of concentric conducting sheaths around said conducting element, insulation separating said sheaths from one another, and means connectingLk groups of said sheaths in series to form separate,auxiliary windings the potentials induced in said sheaths by said field being stepped down from within outwards, as set forth. f

` 3. A winding for electrical apparatus having an electro-magnetic field comprising in combination a. main conducting element having a potentialincreasing along its lengthinduced by said electro-magnetic lield, a single concentric conducting sheath surrounding a portion of said element, a pluralityY of concentric conducting sheaths surrfmnding other portions of said element having higher potentials, insulation separating said sheathsy from one another and from said'conducting element, and means associating said sheaths to form separate auxiliary windings in inductive relation to the said field, the potentials induced in said sheaths being stepped down from within outwards, as set forth.

4. A winding for electrical apparatus having an electro-magnetic field comprising in combination a main conductingelement, and sheathing means composed of different numbers of sheaths surrounding different portions of the conducting element, cert-ain of said sheathing means associated with different portions of said conducting element' being in series, and the voltages inducedy by said field in said ysheaths being stepped down from `within outwards, as set forth.r

5. In combination in a dynamo-,electric machine having anelectro-magnetic .field and a plurality of slots, a main winding consisting of a pluralityof.conducting elements situated in said slots, conducting sheathsfsurrounding certain of saidelements andvarying in number according to the potential induced in said elements by said held, and means connecting certain of said sheaths together in series to form a plurality of separate auxiliary windings having voltages stepped down from within outwards induced therein bysaid field, as set forth.

6. In combination a dynamo-electric inachine havmg an electro-magnetic field and a plurality of slots, a main winding including i a plurality of conducting elements situated in said slots in inductive relation to said field, and' conducting sheaths surrounding certain of said elements in inductive relation to said field and varying in number according to the potentials induced in said elements by said field, means connecting said sheaths together in series, the potentials induced in said sheaths by said field being stepped down from within outwards, as set forth. l

7. A winding for electrical apparatus having an electromagnetic lield and a number of slots con'iprising in combination a conducting element having au e. m. f. induced by said field' and increasing along its length arranged in said slots, one conducting sheath around a portion of said element in certain slots, two conducting sheaths around another portion of said element in other slots, three sheaths around another portion-of said element in li'urther slots, means connecting said single sheaths in series,ineans connecting said inner sheaths wheretwo are employed in series, means connecting the innermost sheaths where three are employed in series, means connecting said three groups in series to form a single and separate auxiliary winding, means connecting said outer sheaths where two are employed in series, means connecting 'said inner sheaths where three are employed in series, means connecting said two groups in series to form a second separate and complete auxiliary winding, and means connect-- ing said Aouter sheaths where three are eniployed to form al third separate and complete auxiliary winding, voltages induced in said sheaths by said field being stepped down from within outwards, as set forth.

8. A winding for electrical apparatus having an electro-magnetic iield comprising in combination a main conducting element having a potential increasing along its length, a single concentric conducting sheath surrounding a portion of said element, two concentric conductingsheaths surrounding anotherportion of said element, three concentric conducting sheaths surrounding a further portion oi said element, insulation separatingV said sheaths from one another and from said conducting element, the voltages induced in said sheaths by said iield being stepped down -from within outwards, and means connecting in series the sheaths wherev vone is.employed,the inner sheaths where two are employed and the innermost sheaths where three are employed to form a single complete auxiliary winding,as set forth.

In testimony whereof 'we have signed our names to this speciiication..

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